Control mechanism



CONTROL MECHANI SM Filed Feb. 8, 1967 INVENTOR Claudio Gf'yzze f' i' "g /w lfd/L50, 557-74 gara/05e @a 42a United States Patent 3,426,979 CONTROL MECHANISM i Claudio Gigante, Milan, Italy, assignor to Trans-Continental Engineering Corporation, Salt Lake City, Utah Filed Feb. 8, 1967, Ser. No. 614,716 U.S. Cl. 242-99 4 Claims Int. Cl. B65h 17/42;B66d 1/50 ABSTRACT oF THE DISCLOSURE A control mechanism for winding and unwinding a normally tensioned exible member. The mechanism incorporates a drum attached to a rotatable shaft with the drum being frictionally locked to a ratchet wheel while tension is applied to the flexible member with the drum being automatically locked to the housing ofthe mechanism when the tension onthe flexible member is released.

The present invention relates generally to devices for raising and lowering venetian blinds and the like and more particularly to an improved control mechanism for winding and unwinding a exible member to raise and lower the venetian blinds or the like. y

The primary object of the present invention is to provide an improved control mechanism for winding and unwinding a flexible member and in which the control mechanism is capable of being automatically locked against rotation at any point of winding or unwinding of the flexible member.

Another object is to provide an improved control mechanism which is small and relatively inexpensive and is capable of raising and lowering relatively large loads applied to the flexible member.

A further object is to provide a winch device for Winding and unwinding a exible member thereon and having frictional contacting elements, the frictional engagement of which is increased as the load on the flexible member is increased.

Other )objects and features of the invention will become apparent-when considered in conjunction with the following specifications and the accompanying drawings wherein, Y

FIGURE l is a side elevational view, with parts broken away, of the control mechanism of the invention;

FIGURE 2 is a vertical sectional view similar to FIG- URE l; and

FIGURE 3 is a sectional View, similar to FIGURE 2, showing a modified form of the invention.

Generally speaking, the control mechanism includes a rotatable shaft having an integral radially extending ange which is in frictional engagement with a ratchet wheel and has a helical threaded outer surface that threadedly receives a drum which has a portion that is capable of receiving a flexible member thereon. The drum has a friction member carried atone end thereof which is normally in frictional engagement with the ratchet wheel when the flexible member is being wound upon the drum and in which the frictional engagement between the ratchet wheel and the drum is increased as the tension on the flexible member is increased. The device further includes locking means including elements carried adjacent the other end of the drum which is capable of being moved axially on the shaft when the tension on the ilexible member is released to thereby lock the drum to a housing encasing the entire structure and a spring biased pin engaging the ratchet wheel to prevent undesired counter-rotation when tension is on the exible member.

As shown in FIGURES 1 and 2, the control mechanism includes a housing 12 which is adapted to be received in a supporting structure 14, such as a hollow casing forming a part of the window frame. The housing 12 includes a dirst portion 13 and a cover portion 15 having anges 16 in frictional engagement with the casing 14 to maintain the housing portion in a predetermined position with respect to the casing 14.

The housing portion 13 has an integral hub portion 20 which rotatably receives a recessed portion 22 of a rotatable shaft 24. The shaft 24 is provided with a collar 26 at the opposite end thereof which is rotatably journaled in a bearing 28 carried by the cover plate 15. The shaft 24 has an opening extending axially throughout its length and has a pair of spaced polygonal configured portions 32 which correspond to the configuration of a portion of the handle 34 received within the opening.

The end of the handle 34 which is received in the opening 30 is provided with a spherical portion 36 that is` frictionally held in an opening 38 of a nonmetallic sleeve 40.

The shaft 24 has an integral radially extending flange 42 adjacent one end thereof and the major portion o-f the outer surface thereof is provided with a helical thread 44. A ratchet Wheel 46 is slidably received on the outer periphery of the shaft 24 and is normally held in frictional engagement with one surface of the flange, in a manner to be described later.

The housing portion 13 includes a lug 50 having an opening 52 therein which slidably receives a pin or pawl 54 that is spring biased into engagementl with the ratchet wheel 46fthrough a spring 56 disposed between the upper end of the pawl 54 and a horizontally disposed projection 58 extending inwardly from the cover 15.

A drum 60 is provided with an internally threaded opening 62 which is threaded upon the helical threads 44 of the shaft 24. One end of the drum 60 has a friction disc 64 secured thereto, which is adapted to be forced into contacting engagement with a second surface of the ratchet wheel 46. The opposite end of the drum includes one or more projections 70 that are adapted to be received in any one of a plurality of recesses 72 formed in the housing portion 13.

One free end of a exible member is received in a slot 82 formed on a portion of the drum 60 with the free end of the flexible member 80 being locked in the slot by means of a threaded screw 84. The flexible member 80 extends through a sleeve portion 9G fixed to the casing 14 and is maintained at a spaced distance from the side walls of the sleeve by a guide member 92 pivotally supported in the upper end of the sleeve 90. The opposite end of the cord (not shown) may be connected to a conventional venetian blind or the like to raise and lower the blind between an open and closed position.

In operation, rotation of the handle 34 and the shaft 24 in a clockwise direction will also rotate the drum 60 in the same direction and the tension on the opposite end of the cord 80 will tend to rotate the drum counter-clockwise with respect to the shaft. IThe combined counterclockwise rotation of the drum and the clockwise rotation of the shaft `will tend to move the drum axially along the shaft into frictional engagement with the ratchet Wheel 46 which will increase the frictional engagement of the flange 42, the drum 60 and the ratchet Wheel 46 as the tension on the cord 80 is increased. Continued rotation of the handle 34 in the clockwise direction will rotate the ratchet wheel 46 with the shaft 24 forcing the spring biased pin upwardly as each of the teeth of the ratchet wheel pass therebeneath.

Whenever rotation of the shaft 24 in the clockwise direction is halted and tension remains on the flexible member 80, the frictional engagement between the ratchet wheel 46 and the friction disc 64 and engagement of the spring biased pin 54 with a tooth of the ratchet wheel will eliminate any counterclockwise rotation of the drum 60. Thus, the member connected to the opposite end of the liexible cord 80 may be stopped at any point along its path of movement by merely discontinuing rotation of the shaft 24.

In order to lower the Venetian blind or the like, the handle 34 is rotated in the counter-clockwise direction and the spring biased pin or pawl 54 will prevent counter clockwise rotation of the ratchet wheel 46. Thus, rotation of the shaft 24 in the counter-clockwise direction will tend to move the drum 60 axially away from the ratchet wheel 46 but this tendency is counteracted by the tension on the cable 80 tending to maintain the drum 60 in frictional engagement with the surface of the ratchet wheel 46. The f-rictional force between the drum and the ratchet wheel can readily be overcome to allow the cord or flexible member to become unwound. However, when the tension on the cord or flexible member 80 is removed, the drum 60 through the threads 44 and 62 will be moved axially away from the ratchet wheel 46 and eventually will force the projection 70 into one of the openings 72 thereby locking the drum with respect to the housing. This unique feature will eliminate the possibility of the continued rotation of the drum after the tension on the flexible member has been removed thereby eliminating the possibility of the flexible member becoming entangled within the housing and on the drum.

It should be noted at this point that one of the unique features of the improved winch device is the fact that as the tension on the cord or flexible member 80 is increased, the frictional engagement between the surfaces of the flange 42, the ratchet wheel 46, and the friction disc 64 is increased. This is necessarily so because the increased tension on the exible member 80 will increase the tendency of the drum to be rotated counter-clockwise as the shaft 24 and handle 34 are rotated clockwise. This feature is of considerable advantage to provide a small and relatively inexpensive control mechanism which is capable of moving extremely heavy loads with respect to the size of the unit itself.

The improved control mechanism disclosed in FIGURES 4 and 5 provides a convenient way of raising and lowering a member, such as a Venetian blind, and holding the member in any position intermediate the opposite ends of movement by automatically locking the control mechanism upon discontinuation of the rotation of the handle 34.

A slightly modified form of the invention is disclosed in FIGURE 3 wherein the parts of the device which are similar in nature to the preferred embodiment are referenced by the same reference numerals with the subscript a. Also, the pawl that cooperates with the ratchet wheel 46a is not shown in FIGURE 6.

The modified form of the invention is particularly adapted for moving relatively heavy loads without any additional force being applied to the handle 34a. In the modified embodiment, the ange 42a is provided with teeth 100 on the outer periphery thereof. The teeth 100 are in constant mesh with the teeth of a gear 102 that is rotatably journaled by a sleeve 104 on a bearing 106 and a second bearing member 108 rotatably journaled in an opening 110 in the housing extension 112 of the main housing portion 13. One end of the handle 34a is received in a polygonal opening 120 disposed axially of the gear 102 and the bulbous portion 36a is received through an opening 122 in a nonmetallic member 124 which is in the form of a hub received on the outer end of the supporting portion of the gear 102.

The modified form of the invention is identical in operation to the preferred embodiment except that the rotation of the handle is in the opposite direction to rotation of the shaft 24a. Therefore, a detailed description of the operation of the modified embodiment does not appear to be necessary.

While' two preferred embodiments of the invention have been shown and described, it will be understood that various changes and modifications may be made without departing from the spirit of the invention as defined yby the following claims:

I claim:

1. A control mechanism for winding and unwinding a flexible member, comprising a shaft rotatably journaled in a housing and having a ange adjacent one end thereof, rotating means engaging said shaft for rotating said shaft in either direction, a helical thread on the external surface of said shaft, a drum having a threaded inner surface cooperating with said helical thread and adapted to be moved axially of said shaft with the exible member adapted to be wound and unwound on said drum and normally tensioned to rotatively bias said drum in a direction urging said drum axially towards said ange, a wheel interposed between said drum and said ange, means on said housing limiting `rotation of said wheel to one direction on said shaft, and locking means on said drum including a friction member on one end of said drum adjacent said wheel to frictionally lock said drum to said wheel while tension is being applied to the exible element and a locking element carried on the opposite end of said drum and adapted to engage said housing when the tension of the flexible member is released whereby said wheel locks said drum to said housing when said cable is tensioned and rotation of the shaft is terminated and said locking element locks said drum to said housing when no tension is on said cable.

2. A control mechanism as defined in claim 1, in which said shaft `is a hollow member and said rotating means includes a handle having a portion received in said hollow member with nonmetallic means for releasably retaining said handle in said member.

3. A control mechanism as defined in claim 1, in which said rotating means includes a gear rotatably journaled in said housing and in constant mesh with teeth formed on said iiange.

4. A control mechanism as defined in claim 1, in which said drum includes a slot lfor receiving one end of said flexible member and releasable means for locking the free end of the tiexible member in said slot.

References Cited UNITED STATES PATENTS 889,961 6/ 1908 Percival 242-99 2,357,462 9/ 1944 Ferguson 254-187 2,811,322 10/1957 Wilkinson 242-12S.1 X 3,143,316 8/ 1964 Shapiro 242-96 FOREIGN PATENTS 794,770 12/1935 France. 444,375 1/ 1949 Italy. 560,259 4/ 1957 Italy.

WILLIAM S. BURDEN, Primary Examiner.

U.S. Cl. X.R. 

